We propose to produce cell lines derived from the adrenal zona glomerulosa and fasiculata which maintain important phenotypes of the natural tissue. We will use 2 basic methods for the production of these cell lines. First, we will introduce oncogenes into purified isolated adrenal cortical cells using a retroviral vector. Secondly, we will produce transgenic mice specifically expressing oncogenes in the adrenal cortex by using the promoter region from the adrenal specific steroid 21-hydroxylase gene. Several oncogenes will be utilized including temperature sensitive mutants. Resulting cell lines will be screened for production of end products of differentiated adrenal cortical cells, aldosterone for the glomerulosa cells and corticosterone for the fasiculata cells. In order to determine their suitability as models for the natural adrenal cells, cell lines secreting these steroids will be further characterized. Their responses to steroid secretagogue, receptor repertoire, activation of intracellular second messengers (IP3, DAG, Ca++) , and electrophysiologic properties will be determined. Methods for genetic manipulation of these cell lines will be developed and applied to 1) investigation of the effects of the local renin-angiotensin system on aldosterone secretion, 2) elucidation of the intracellular pathways leading to stimulation of steroid secretion and 3) the mechanism of long term cellular adaption to changes in environment (as a model for changes in adrenal sensitivity caused by alterations in dietary Na+ or K+). We also expect these cell lines to greatly facilitate studies which are currently performed on acutely dispersed adrenal cells. These studies will further our understanding of the changes in adrenal sensitivity caused by dietary manipulations and the role of the adrenal in blood pressure homeostasis.